/Engine/Plugins/Experimental/GeometryScripting/Source/GeometryScriptingCore/Public/GeometryScript/ShapeFunctions.h
Compute the pair of closest points on a 3D Ray and Line Segment The Line Segment is defined by its two Endpoints.
the minimum distance between the Ray and Segment, ie between RayPoint and SegPoint
static double GetRaySegmentClosestPoint ( FRay Ray, FVector SegStartPoint, FVector SegEndPoint, double & RayParameter, FVector & RayPoint, FVector & SegPoint )